1. Field of the Invention
The present invention is related to an optical reader employing a camera that captures an optical image of a stack of documents and converts it to a digital image. The top document typically is the document of interest, in that the top document is to be identified and the printed and man-made marks on that document are to be read, is understood and processed.
“Camera” includes any device that captures a scene on a photo-sensitive media that may in turn be scanned or read out and down loaded to a computer processing system. The captured scene is digitized into a captured digital image of pixels that are stored in a computer memory. Lenses, optical filters, apertures, etc., and the photo-sensitive media or surface, array or arrays may all be included in the term “camera.”
2. Background Information
Printed documents, including, e.g., lottery play slips, scratch tickets, instant tickets and the like are collectively defined herein as “forms.” Such forms may provide locations for an individual to indicate a specific intent that may be reflect, e.g., by placing a check mark or filling in a box that is printed on the form. Correctly identifying the form, and reading and processing the printed and man-made marks that are disposed on the form are not simple tasks.
In order to increase the speed of reading and processing forms, it has been suggested that a first form to be read is placed on a platen viewed by a camera, where the camera optical image is digitized and processed in a computer system. After processing the first form, another form may be simply laid on top of the first form and processed. Successive forms may then be laid one on top of another, without the need for alignment or registration, and processed.
Leaving the prior read forms in place and not having to feed each form, e.g., into a tractor drive improves efficiency by speeding the reading and processing of successive forms. One limitation, however, is that the top form may be difficult to distinguish and read due to the presence of the underneath forms, portions of which may still be visible to the camera. Moreover, one or more of the forms may be bent or crumpled, and/or the lighting may be insufficient or shadows may encroach on the form making reading is difficult.
Still other limitations in reading forms that are “stacked” or laid one on top of another typically stem from the forms being of different sizes, and including different printed symbols, words, titles, etc. When these various forms are haphazardly stacked upon one another, the camera scene includes the top form and will also include portions of many of the underneath forms.
FIGS. 1A and 1B illustrate the problem. In FIG. 1A, a stack of forms are laid one on top of each other. In this case, a series of LOTTO forms and at least one KENO form are evident. Of particular interest is that it is not evident which form is on top. One difficulty is the inability to distinguish the edges of the top form. Since forms may have printed artifacts that are not square or at right angles, the edges cannot be found simply by looking at the large printed texts. For example, as shown in FIG. 1A, the top form may be the KENO 2, the LOTTO 4, the LOTTO 6, the LOTTO 8, or the GTECH 10.
FIG. 1B illustrates the ease of distinguishing the top form when the edges of the top form are distinguished, as indicated here by the dotted line 12.